In a construction machine equipped with a replaceable attachment such as a hydraulic excavator, a user performs work by appropriately changing an attachment such as a bucket, a nibbler, and a breaker according to the work. If the construction machine fails to recognize information such as a size of the attachment, interference prevention control for preventing interference of the attachment in a cab and operation control of a work device according to the attachment (for example, automatic horizontal pulling control of a bucket) may not function effectively. Therefore, the construction machine needs to recognize the currently installed attachment.
As a method for recognizing an attachment and a method for measuring a size of an attachment, Patent Literatures 1 and 2 are known.
Patent Literature 1 discloses a technique in which, when a service person replaces an attachment, the service person inputs identification information about the attachment and transmits the identification information together with the input date and time to a terminal device, and then the terminal device manages the attachment installed in a construction machine.
Patent Literature 2 discloses a technique to obtain a difference in measurement data of a predetermined part between a standard attachment and a replacement attachment when the standard attachment serving as an attachment before replacement and the replacement attachment are set in a predetermined measurement posture, and to calculate numerical data about a size and shape of the replacement attachment based on the obtained difference and previously stored numerical data about the size and shape of the standard attachment.
Specifically, in Patent Literature 2, a posture of a bucket is set in a posture in which a tip is brought into contact with the ground to cause an upper surface to agree with a vertical direction before and after bucket replacement, angles of a boom and an arm are measured, and the measured angles are substituted into a predetermined arithmetic expression to obtain an attachment length.
However, Patent Literature 1 is based on manual input of the identification information by the service person, causing a problem that human error such as input error and forgotten input occurs.
Patent Literature 2 has a problem that measurement takes time because both attachments of the standard attachment and the replacement attachment are set in the measurement posture by an operator's operation. Also, Patent Literature 2 has a problem that, since it is necessary to measure the standard attachment serving as an attachment before replacement, if measurement work is neglected at the time of replacement of the attachment, the replacement attachment cannot be recognized.